Method and apparatus for detecting the collision of data packets utilizing a preassigned transceiver code in the preamble
US4888763A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 1988 |
| Grant date | Dec 19, 1989 |
| Priority date | — |
| Expiry date | Mar 11, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/06
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Through the method and apparatus of the present invention the collision of two packets can be detected with a high degree of accuracy under a variety of conditions. The preamble of each packet transmitted is modified to include collision detection data comprising an initial pulse having an amplitude sufficiently high to be detected even when attenuated and having a pulse width twice the normal data pulse width followed by a transceiver code of a predetermined length unique to each transceiver. Thus, in the event two packets collide, the collision may be detected by recognizing a second large pulse within a time period less than the sum of the packet duration and the gap between packets, by determining if a large initial pulse has a pulse width larger than the generated pulse width, and by determining if the transceiver code echoed back to the transmitting transceiver is equal to transceiver code stored in memory on the transceiver. If a transceiver detects a collision, a large collision detect pulse having an amplitude and pulse width similar to the amplitude and pulse width of the large initial pulse is transmitted within the time period less than the sum of the packet duration an…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.